表面活性剂与纵向微沟槽协同减阻实验研究

Based on the principle that the scale of near-wall vortices could be enlarged in the drag-reducing surfactant solution and the longitudinal microgrooves could reduce drag by restricting the motions of near-wall streamwise vortices, the possible complementary mechanism of drag reduction with surfactant and microgrooves was proposed, and their collaborative drag-reducing performance was verified by experiments. The collaborative drag-reducing performances of 0.22 mmol/L CTAC/NaSal surfactant solution in longitudinal microgroove channels with different sizes at different temperatures were investigated. It is found that the drag reduction performance of 0.22 mmol/L CTAC/NaSal solution can be enhanced by microgrooves at 20℃, the maximum drag reduction rate increases from 66% in smooth channel to 71% in G1 channel and 74% in G2 channel, respectively. The critical Reynolds number and critical temperature of drag-reducing solution in G1 channel are lower than that in G2 channel, but they are almost the same for G2 channel and smooth channel. The drag-reducing size of microgroove could be enlarged in the drag-reducing solution. The collaborative drag-reducing mechanism of surfactant and microgroove might be that the scale of near-wall vortices is enlarged in surfactant solutions, resulting in that microgrooves restrict more near-wall streamwise vortices and maintain the drag reduction performance at higher Reynolds number.